Hip pain can have a significant burden on function and quality of life. While there are many causes, prevailing research shows that hip pain is common in both athletic and older populations (1,2). In athletes, groin pain accounts for 10% of all visits to sports medicine centers, and groin injuries account for up to 6% of all athletic injuries (1). In older adults, a diagnosis like osteoarthritis is common, and is ranked as the eleventh highest contributor of global disability (2). While research often focuses on specific populations of people or diagnoses, when put together, it reveals that general hip pain is a common problem affecting a significant portion of the general population. There are many diagnoses that exist to describe hip pain, with the ultimate goal to develop the most effective course of treatment. Traditionally, when someone with hip pain visits a doctor, a physical examination will be performed, which includes assessing for tenderness, swelling, or redness, and determining the range of motion at the hip joint. The doctor may also recommend imaging, such as an x-ray or MRI, as well as lab tests (3). While this can provide a physician with valuable information, such examinations have the risk of missing causes of pain from nearby structures, such as the pelvic floor.

The pelvic floor muscles are three layers of muscles that attach to the lower aspect of each half of the pelvis from side-to-side and from the pubic bone to the tailbone, front-to-back. These muscles support the pelvic organs, as well as contribute to trunk stability, and play a significant role in bowel and bladder control and efficiency, as well as sexual function (4). The muscles that make up the deepest of the pelvic muscles, include the levator ani and coccygeus, as well as the obturator internus on the sides (5). The pelvic floor is interconnected to many key structures in the body, and dysfunction here can affect seemingly unrelated parts of the body. Below are two cases of unresolving hip pain, where assessment and treatment of the pelvic floor helped to promote a return to recreational activities.

Case 1: A BICYCLIST

A 32-year-old male professional cyclist came to physical therapy with complaints of pain in his right hip and groin, mainly with prolonged sitting and cycling. This began soon after he suffered severe bruising on his right hip from a fall, with a tear of two hip muscles (tensor fascia lata on the front and gluteus medius on the side). Prior to this, he had a history of multiple leg injuries due to cycling, but had never complained of any pelvic floor issues. Upon examination, decreased hip range of motion was also discovered. Initially, he received ten sessions of “standard physical therapy,” which included stretching, joint mobilization, soft tissue release, dry needling, and exercise.

However, after only minimal improvement, he was referred to a pelvic floor specialist for further evaluation where increased muscle tone and tenderness in multiple pelvic floor muscles (both obturator internus muscles and both iliococcygeus muscles) were discovered. Also, weakness of a pelvic floor contraction was also noted (6). Based on response to treatment, his hip pain decreased significantly from his current treatment of pelvic floor dysfunction, though it was completely missed in the initial testing.

But how does pelvic floor dysfunction contribute to hip pain? The correct treatment was missed because this connection was missed. Consider the anatomy and mechanics of the hip and pelvis. The gentleman described above is a professional cyclist, which means that whenever he is on his bicycle, he must flex (bend) his hip up to 90 degrees. More hip motion does not tend to occur because it would cause the pelvis to become unstable on the small seat (7). When the hip is bent, the femoral head (ball of the ball-and-socket joint) must flex (bend up), abduct (move to the side), and rotate in towards the groin (8). As the pedal is pushed downward, the hip moves into an extension (straightening) position. Although the hip never reaches a fully straightened position when cycling because he is seated, the hip moves through between 40 and 43 degrees of total motion with each cycle of the pedal (7). So, when the hip is moving into that straightened position, that femoral head must extend (move back), adduct (move sideways toward the groin), and rotate out away from the groin. While the movements of ball of the hip are small, as they are occurring with the confines of the socket in the pelvis, it is important to remember what muscles are in close proximity (8).

Besides the extensive list of hip flexors and gluteus muscles, there are several muscles that sit on the inner side of each hip and the bottom layer of the pelvis – the muscles of the pelvic floor. The two muscles that are of the most interest in this case are the obturator internus and the iliococcygeus muscles, as tightness and tenderness were found in each pair. The obturator internus muscle contributes to the walls of the pelvic floor, on each side of the pelvis. and sits on the inner side of the hip joint. The iliococcygeus muscle attaches on one end into the tendinous arch of the obturator fascia, so there is only dense connective tissue joining this muscle and the obturator internus (5).

When the hip is in a bent position the obturator internus muscle abducts the hip, or moves it to the side, away from midline; however, when the hip is extended (straightened) this muscle rotates the hip outward. For the iliococcygeus muscle, its role is one of support for the pelvic contents and lifting for the pelvic floor (5). Considering all these factors, it can be theorized that when the hip is in a bent position at the top of the pedaling cycle the obturator internus is activated through the abduction (sideways) motion of the ball of the hip, and continues to be activated as the hip straightens since the ball is rotating outward. Furthermore, because the iliococcygeus muscle is attached to the obturator internus muscle through a dense strip of connective tissue, it must work harder to help support this obturator muscle throughout the cycling activity. Thus, these muscles have become overused and shortened with regular and intense cycling required of a professional, who likely had some abnormal muscle activation or movement strategies prior to his pain due to previous injuries.

With the specially trained pelvic floor physical therapist, the pelvic floor connective tissue was mobilized internally over two treatment sessions, in addition to the cyclist performing hip stabilizing exercises. After the first session, there was an immediate and significant improvement in hip range of muscle and pelvic floor muscle contraction; furthermore, sitting pain was resolved. After the second session (7 days later) this gentleman was discharged from PT as he was pain free in sitting and cycling. In a follow up call one month after discharge, he was still pain free without altering training (6). This dramatic change occurred because the release of connective tissue in the pelvic floor decreased tension and trigger points in the obturator internus and iliococcygeus muscles. Thus, his hip range of motion and pain were normalized, and he was able to return to competitive cycling without restrictions.

Case 2: A RUNNER

A 45-year-old female was referred to physical therapy by her gynecologist with an initial diagnosis of left hamstring strain, toward the top of the thigh, related to distance running. This woman was an experienced marathon runner, who ran an average of 30-40 miles per week. She presented to her first PT appointment with pain in her left sit bone, with diffuse aching radiating into her left buttock and pubic bone; she stated her pain began about 4 months prior to her first PT session. The mechanism of injury was “pulling a muscle” while trying to avoid falling on a trail run. At that time, she immediately felt pain near her sit bone, but was able to complete her run. Eventually, as her symptoms progressed, she stopped running, and was only able to tolerate about 15 minutes of sitting. By her fourth PT visit, her pain had decreased, but continued mildly with sitting and shifted into her left pubic bone. She also reported a deep ache that could not be touched from the outside. She was referred to a pelvic floor specialist for further evaluation; upon internal assessment of the pelvic floor, significant tenderness and reproduction of the “deep ache” was found in her left levator ani and obturator internus muscles, as well as increased muscle tone. Furthermore, contraction of these muscles was weak, and she presented with poor relaxation of the same muscles. (9).

The hamstring muscles attach to the sit bone, and in running help to extend the hip and control the knee (10). Due to the location of this woman’s complaints, initial treatments focused on pain management, such as sitting on a wedge or donut to relieve pressure on her sit bone, as well as core strengthening exercises like the plank, and gluteus and hamstring strengthening exercises. Since the patient reported relief of sit bone pain, except with prolonged sitting by her fourth visit, it was logical to directly address the hamstring and gluteus muscles; however, these are not the only muscles in the area of the hip (9).

When this woman was assessed by a pelvic floor specialist, weakness, tightness, and tenderness were discovered in her obturator internus and levator ani muscles on the side of her pain (9). As discussed in the first case, the obturator internus muscle makes up part of the wall of the pelvis and sits just inside of the pelvis, past the hip joint (5). With running, an efficient hip will move between 50 degrees flexion (bending up) and 10 degrees of extension (straightening back) (10). Thus, when the hip is flexing, the obturator internus is likely assisting with abduction of the ball of the hip joint, and when the hip is extending the obturator internus muscle is likely active in outward rotation of the ball (5,8). The levator ani muscles attach from the pubic bone in the front to the back portion of the pelvis, and play an important role in stabilizing the pelvis and the pelvic contents (5). Considering the mechanics of running, the obturator internus and levator ani muscles were likely working hard to promote a good running pattern, and when she tripped on a run, these muscles were overexerted. Then they continued to overwork to compensate for the pain and weakness demonstrated by her hamstring muscles.

In addition to exercises for hamstring and gluteal muscles, internal release of the left levator ani and obturator internus muscles was performed, as well as gentle isometric contractions for strengthening and lengthening of pelvic floor for relaxation. After 7 additional sessions over a 2-month period, this woman’s pain had decreased greatly, she was able to tolerate sitting for more than two hours, she was able to hop on her left leg without pain, and her hip and pelvic floor muscle strength improved. After six months, she had returned to running, and had recently completed a marathon without pain (9).

Conclusion

In summary, augmenting treatment with the addition of direct pelvic floor interventions in each of the above cases significantly improved each person’s remaining symptoms, and allowed them to return to their prior activities without restrictions. This demonstrates the importance of considering the pelvic floor in the diagnosis and treatment of hip pain – these patients both had injuries that were initially missed because the pelvic floor was not considered as a possible cause of hip pain, yet emerging evidence is linking pelvic floor dysfunction to otherwise intuitively unrelated injuries. This also highlights the need for further research in this area to minimize the occurrence of unnecessary procedures and medications, and to ensure that individuals can return to their daily activities with minimal disruption of their quality of life.

If you or someone you know is struggling with unresolving hip pain, make an appointment with a pelvic floor physical therapist today for further assessment. Feel free to contact our midtown office at 212-354-2622 or our downtown office at 212-267-0240, or visit our website (www.beyondbasicsphysicaltherapy.com) for more information! We are offering free phone consultations at both offices for a short period!